Gate for foundry sand hopper



Aug. 4, 1970 F. A. HULET 3,522,927

GATE FOR FOUNDRY SAND HOPPER Original Filed July 15, 1966 3 Sheets-Sheet 1 ll 29 39 I9 4| 3| jig. Z.

INVENTOR FRANK A. HULET 3 4 2, mi WV v A TTORNEY g- 4, 0 F. A. HULET I 3,522,927

GATE FOR FOUNDRY SAND HOPPER Original Filed July 15, 1966 3 Sheets-Sheet 2 22 32 42 40 30 2| I3 l l l l I I INVENTOR FRANK A. HULET A TTORNE Y Aug. 4, 1970 HULET 3,522,927

GATE FOR FOUNDRY SAND HOPPER Original Filed July 15. 1966 3 SheetsSheet 3 P E v h i A I AREA PILOT v PRESSURE United States Patent 3,522,927 GATE FOR FOUNDRY SAND HOPPER Frank A. Hulet, Hutchinson, Kans., assignor to M. W. Hartmann Manufacturing Co. Inc., Hutchinson, Kans., a corporation of Kansas Continuation of application Ser. No. 565,461, July 15, 1966. This application Sept. 12, 1968, Ser. No. 767,897 Int. Cl. F16k 1/18 US. Cl. 251-29 2 Claims ABSTRACT OF THE DISCLOSURE A clam-shell type discharge gate for the outlet of a bin for foundry sand mixtures is provided with means for rapidly opening and closing the outlet, accompanied by the striking of the closing members against each other in the closed position, and the striking of the half clam-shell members against rigid stops at the end of fully open positions, provides smooth even flow of dispersed and fluffed moistened sand mixture into casting flasks or containers disposed below said gate.

This application is a continuation of the copending application of Frank A. Hulet, Ser. No. 565,461, filed July 15, 1966 for Gate for Foundry Sand Hopper, abandoned coincident with the filing of this application.

This invention relates to a gate for a foundry sand hopper and in particular to an oscillatory and chattering gate which distributes foundry sand into foundry flasks or other containers.

One object of the invention is to provide a hopper gate which discharges dispersed moist sand from a hopper or bin into a foundry flask or other container. Another object is to provide a hopper gate structure of the clam-shell type which may be closed and opened in rapid sequence to discharge granular material such as moistened sand in an even shower of dispersed particles. Another object is to provide pneumatically actuated air valves to produce the rapid alternating opening and closing of a clam-shell type gate in response to a pilot or signal valve means which is actuated by the movement of a gate.

These and other objects are attained by my invention which will be understood from the following description, reference being made to the accompanying drawings in which FIG. 1 is an end elevational view of a gate of the clamshell type adapted for attachment to the bottom of a hopper, and showing air cylinder means for actuating the gate, the gate halves being in closed relation;

FIG. 2 is a side elevational view of the gate structure showing mechanical and pneumatic air control valves;

FIG. 3 is an end elevational view of the gate end opposite that shown in FIG. 1;

FIG. 4 is a partial top plan view showing about onehalf of the gate structure;

FIG. 5 is a diagram showing the connecting piping of the air control valves and air cylinder operating means for the gate means;

FIG. 6 is a diagrammatic view depicting paths of air flow through the shuttle valve;

FIG. 7 is an axial section through the signal valve; and

FIG. 8 is an axial section through the cut off valve.

Referring to the drawings which show a preferred form of the invention, the gate body 11 is a rectangular member, unitary or fabricated, having end walls 12 and 13 and connecting side walls 14 and 15, all of which are provided with outtnrned flanges 16 adapted for connection to the 3,522,927 Patented Aug. 4, 1970 which are suspended the two half shells 23 and 24 of the gate. Each of the half shells 23 and 24 consists of opposed segmented end members 25 and 26, and 27 and 28, with counter arms respectively 29, 30, 31 and 32 extending beyond the sleeve bearings 43, 44, 45 and 46, by which the end members are swingably supported respectively on the pivot pins 19, 20, 21 and 22, mounted on the brackets.

Each of the two half shells 23 and 24 has a curved sheet metal closing plate, 33 and 34, attached to the respective pairs of segmental end members, 25 and 26, and 27 and 28. The adjacent inner edges of the closing plates 33 and 34 come together in abutting relation when the half shells 23 and 24 are in closed position (as in FIG. 1). Protective bumper plates 35, 36, 37 and 38 are provided at the ends of the abutting edges.

The opposed pairs of counter arms 29 and 30; 31 and 32, are provided with intermeshing gear teeth 39, 40, 41 and 42 so that the half shells will move in synchronism.

An air operated piston and cylinder unit 47 is operatively connected to the segmental end members 25 and 27 at one end of the gate, so that when the piston rod 48 is extended from the cylinder 49, the two half shells 23 and 24 are pushed away from each other and the gate is opened; and when the piston rod 48 is retracted, the gate is closed.

The flow of compressed air to the ends of the air cylinder 49 is controlled by a pneumatic shuttle valve 60 (for example, No. FR 120 made by Valvair, Akron, Ohio). This shuttle valve is illustrated in FIG. 6. A gate actuated signal valve 70, with spring return means (for example, the three way open end exhaust valve No. 18-23-25 made by Valvair Co., Akron, Ohio), illustrated in FIG. 7, and a hand operated cut-off valve 80, FIG. 8, are provided respectively in the compressed air lines 67 and 71. The air supply line 81 from the source of compressed air is connected to the cut-off valve 80 at port 82 and also to the entry port 61 of the shuttle valve 60. The exit port 83 of the cut-off valve 80 is connected to the entry port 72 of signal valve 70 by the pipe line 71. The exit ports 63 and 64 of the shuttle valve 60 are connected respectively to the closed end of the cylinder 49 and the opposite or piston rod end of the cylinder pipe lines 65 and 66 respectively. An exhaust port 68 discharges to the atmosphere.

The stem of the signal valve 70 is provided with a contact knob 76 which makes contact with the boss 77 on the closing plate 33 of one' gate half-shell 23 when the gate is at the maximum open position determined by the positioning of the stop bars 56, 57, 58 and 59, on the end walls 12 and 13 of the gate body 11.

A pull cord 84 is operatively attached to the plunger 85 of the cutoff valve 80, for manual opening of said valve against an internal biasing or closing spring (not shown).

The operation of the gate mechanism which results in repeated and rapid opening and closing of the gates will be described with particular reference to the diagram of FIG. 5 and the illustrations of the valves 60, 70 and 80 in FIGS. 6, 7 and 8.

A supply of air under pressure is in continuous communication with the pipe line 81. As pipe line 69 is connected to pipe line 81 in advance of port 82 it bypasses cut-off valve 80 and signal valve 70. Thus air under pressure is continuously delivered to port 61 of shuttle valve 60. In the off position of cutoff valve 80 this pressurized air in shuttle valve 60 is eifective on one face or side of the plunger therein to hold it in position establishing communication through the shuttle valve 60 from port 61 to port 64 which supplies air to one end of the piston in cylinder piston actuator 49 to move this piston to the left, speaking with reference to FIG. 5, and thus hold the gates in closed position.

When a pull is exerted on cord 84 the valve 80 is opened and air under pressure passes from line 81, through valve 80 and line 71 to the signal valve 70. The latter is maintained in open position, that is the position establishing communication from port 72 through the valve to port 73, by the spring 75. Thus air under pressure is delivered to the shuttle valve 60 on the face or side of the plunger thereof, opposed to the face receiving air under pressure from the port 61.

The plunger of shuttle valve 60 is moved by this pressurized air coming from port 62 to the left, speaking with reference to FIGS. and 6 and closes port 64. At the same time port 63 is opened to establish communication from port 61, through valve 60 to port 63 thereof. Line 65 delivers this air to the left hand end of actuator 49 to move the piston of this actuator to the right, speaking with reference to the illustration of FIG. 5. This causes opening movement of the gates.

When boss 77 on one of the gates engages the knob 76 of signal valve 70 (when the gates reach their limit of opening movement) the signal valve 70 is closed so far as communication between the lines 71 and 67 is concerned. However, the port 74 is opened so that air from line '67 is exhausted to the atmosphere through the port 74. This relieves the pressure on the side of the plunger of shuttle valve 60 adjacent port 62 thereby permitting air from port 61 to again be effective on the plunger of the shuttle valve to move this plunger into position closing port 63 and opening port 64.

Air from port 64 now enters the port 50 of the cylinder of actuator 49 and moves the piston thereof to the left, speaking with reference to the showing of FIG. 5. As this piston is mechanically connected to the gates the latter are moved to closed position.

As this action takes place the boss 77 is moved away from the knob 76 whereby the spring 75 is effective to actuate the signal valve 70 to close port 74 and again establish communication between lines 67 and 71.

' As mentioned above the movement of the gates is very rapid and they move from opened to closed position in the time required for the shuttle valve to change its position and again start the cycle. This cycle is repeated as long as the cutoif valve 80 is held open.

When air under pressure is delivered to one end of the cylinder of the actuating mechanism 49 it is exhausted from the other end. As shown in FIG. 5 the exhaust from one end is from port 51, through line 65 to port 63 of shuttle valve 60 and through the latter to port 68. For the other end it is from port 50, through line 66 to port 64 and through shuttle valve 60 to port 68 thereof. Thus the shuttle valve 60 not only controls the delivery of air under pressure to opposite ends of the actuating mechanism 49 but also the exhaust of air therefrom.

Sand compositions which are prepared for making molds for metal castings are usually moistened mixtures containing not only sand, but clays and other binding materials, and these compositions do not fiow readily as does dry sand, but have a tendency to agglomerate into lumps or masses.

The chattering or rapid opening and closing of the gate, with incidental striking of the stops and jarring of the hopper, gives the advantages of smooth and dispersed flow of moistened foundry sand from the hopper; flufis the material instead of feeding out large chunks of 4 compacted sand, and permits metering a selected amoun of sand, merely by pulling or releasing the pull cord on the shut-off valve. The gates cease oscillation only at the closed position.

While the preferred form has been described to illustrate this invention, it will be understood that variations may be made in the details of construction without departing from the invention as defined in the appended claims.

What is claimed is:

1. In gate means for a foundry sand hopper having a discharge end, a pair of pivoted gates disposed in opposed relation across said discharge end, mechanical connections between said gates whereby they are movable simultaneously to an open position, or to a closed position, a double acting pneumatic piston and cylinder operatively connected to said gates to cause movement thereof, a supply of air under pressure, and control means for directing the flow of air from said supply to one end or the other of said cylinder and simultaneously exhausting air in the opposite end, said control means comprising: a pneumatically operated shuttle valve including a movable plunger, and a gate actuated signal valve operatively connected to said air supply, a connection between said signal and shuttle valves connecting with one side of said plunger, and an air line from said air supply to said shuttle valve by passing said signal valve, said signal valve being closed by contact with one of said gates when said gates approach maximum open position to cause air under pressure from said air line to be eifective on the other side of said plunger to move the plunger to a position delivering air under pressure to said pneumatic cylin der end which eifects closing of said gates, and simultaneously vents air to atmosphere from the opposite end of said pneumatic cylinder, said signal valve being restored to open position by release of said gate contact whereby the plunger of said signal valve is returned to its initial position.

2. Control means for causing rapid reciprocation of a piston in a pneumatic cylinder by introducing air from a supply of air under pressure to one end of said cylinder While simultaneously exhausting air from the opposite end of the cylinder, said control means comprising a pneumatically operated shuttle valve having a movable plunger, a signal air valve, an operating member for said signal valve actuated by said piston, a connection between said signal and shuttle valves communicating with one side of said plunger, and an air line from said supply to said shuttle supplying air under pressure to the other side of said plunger when said signal valve is closed by actuation of said arm to move said plunger in a direction opposite to the direction of movement caused by air from said connection when said signal valve is open.

References Cited UNITED STATES PATENTS 543,182 7/1895 Hunt 251-212 X 875,021 12/1907 Westbrook 251212X 1,041,636 10/1912 Lamoreaux 25l-212 X ARNOLD ROSENTHAL, Primary Examiner US. Cl. X.R. 

